It should cite those who had the idea or ideas first, and should also cite those who have done the most recent and relevant work.
You should then go on to explain why more work was necessary (your work, of course.) Quarantine your observations from your interpretations.
You should draw the reader in and make them want to read the rest of the paper.
The next paragraphs in the introduction should cite previous research in this area.
The text fills out the details for the more interested reader.
"Show them, don't just tell them…" Ideally, every result claimed in the text should be documented with data, usually data presented in tables or figures.
Be sure to include a hook at the beginning of the introduction.
This is a statement of something sufficiently interesting to motivate your reader to read the rest of the paper, it is an important/interesting scientific problem that your paper either solves or addresses.
We would like you to gather evidence -- from various sources -- to allow you to make interpretations and judgments.
Your approach/methods should be carefully designed to come to closure.